Monday, June 28, 2004

Stemming the Flow: One of the most tragic illnesses that can befall a person is a sudden bleed into the brain, usually when an aneursym bursts or from trauma to the head. Reports from a stroke conference suggest that there might be new hope in a drug that's used for hemophilia:

An international study involving 400 patients found that a single infusion of the drug, a synthetic version of a naturally occurring protein, given within three hours after onset cut by about one-third the risk of death or severe disability among patients in the midst of a bleeding stroke."

..."The results we've seen are just so eye-popping that I have no doubt that eventually this is going to become the standard treatment for stroke around the world," said Mayer, who unveiled his findings at the World Stroke Congress in Vancouver. "The results are so clear, so consistent and so robust it is truly remarkable."

....In the study, designed primarily to test the drug's safety and potential for reducing bleeding, patients received an intravenous infusion of either the drug, given in one of three different doses, or a placebo. A CAT scan 24 hours after receiving the treatment showed that any of the three doses reduced by about half the amount of bleeding in the brain, Mayer said.

But when the researchers followed the patients for three months, they found that those receiving the drug were approximately 30 percent less likely to die or be left severely disabled -- paralyzed or in a coma. About 70 percent of those who received the placebo either died or were left severely disabled, compared with about 50 percent of those receiving the drug, Mayer said.

"On average, for every six patients you treat, you are going to eliminate one death or severe devastation," he said.

....The study was funded by the drug's maker, Novo Nordisk of Denmark, but Mayer said he has no financial interest in the company or the drug.

Dr. Mayer's eyes are popping, but the rest of the attendees interviewed in the story seemed cautious:

Some researchers, while praising the findings, cautioned that the drug carries risks. More testing was needed to gauge the relative risks and benefits, especially because the trial was not specifically designed to prove effectiveness, they said.

And since, the data were shared at a meeting rather than in a journal, we in newspaper-reader-land can't evaluate them. (Although 50% morbidity compared to 70% for placebo sure seems promising.)

Actually, there are two chain reactions in the clotting mechanism, the intrinsic pathway, which gets kicked off when a blood cell comes into contact with a damaged cell surface (such as it would find in an injured blood vessel wall), and the much faster extrinsic pathway, which gets its kick-start from a protein on cell surfaces called tissue factor. Coagulation Factor VIIa is crucial to both pathways, so it isn't inconceivable that it could prove of immense benefit against hemorrhage.

The drawback is that it induced clotting elsewhere in the body, too, so it has the potential to increase the risk of heart attacks or even strokes caused by clots. And that's why there's a lot more work to be done before it makes it to the bedside.